Web winding mandrel



April s, 1960 E. D. NYs'rRANDV WEB WINDING MANDREL Original Filed May 12, 1955 IN VEN TOR.'

ATTORNES.' l

United States Patent WEB WlNmNG MANDREL Ernst Daniel Nystrand, Green Bay, Wis., assignor to Paper Converting Machine Co., Inc., Green Bay, Wis., incorporation of Wisconsin Original application May 12, 1955, Serial No. 507,822.

Divided and this application December 10, 1956, Serial No. 627,347

2 Claims. (Cl. 242-72) This invention relates to a web windingmandrel and is particularly useful in the rewinding of thin paper webs from a parent roll. The web winding mandrel of this invention may be used, for example, in the automatic web rewinding machine disclosed in the application of Edwin M. Kwitek and Ernst D. Nystrand, Serial No. 299,108, filed July 16, 1952, now Patent No. 2,769,600.

This application is a division of my copending application, Serial No. 507,822, filed May 12, 1955.

While the web winding mandrel of this invention may be used in a variety of environmental conditions and with various web winding machines, it is desired in order to provide a setting for the invention to the end that the invention will be better understood, to describe briefly a web winding machine with which the invention may be used, and in such description reference will be made in particular to the web winding machine disclosed in the above-identified patent application. y

vThe machine there disclosed comprises a turret that is adapted to be rotated intermittently to move a plurality of elongated mandrels extending laterally therefrom through a plurality of operating stations. At one station the mandrels, which are supported in a cantilever fashion, have an elongated paper core inserted thereover. The core-equipped mandrel is then moved to a second station wherein the core is severed into a plurality of relatively short segments. At such time the core is locked on the mandrel. Thereafter the core-equipped mandrel is moved through a glue station wherein an adhesive or glue is applied to the segmented core, and next the mandrel is moved toward a winding station wherein a thin paper web is secured to the glued core, and .the mandrel rotated so as to wind the web upon the core. During the Winding operation the web isv slit longitudinally into a plurality of strips having substantially the same width as the core segments. Following the Winding of a predetermined lamount of web onto the segmented cores, the mandrel is again moved to a further station, and at this time the web is severed and thereafter the severed end of the Web is secured to the web roll that has been wound on each of the segmented cores. In a subsequent stripping station the core is released from the mandrel and all of the segmented cores with their wound webs are stripped from the mandrel preferably byV automatic machinery.

In the web rewinding stations the mandrels initially must be rotated at a relatively high rate of speed, and the speed of rotation must progressively decrease as-the amount of web wound upon the core increases in thickness. The speed of the rotating mandrel, and particularly the decrease in the rotational speed thereof as the webbing wound thereonincreases in thickness, is controlled bythe tension applied against the mandrely by the pin paper web. Thus, the webbing itself and the speed with which it is drawn from a parent roll determines the rotary' speed of the mandrel and brings about a decrease inthe speed thereof as progressive layers of webbing are wound upon the cores. f. As-has been brought out before, it is clear that the ice core, or the segmented core sections, must each be'locked upon the mandrel so that when the mandrel rotates the core segments rotate therewith. The means employed for locking the core segments upon the mandrel must be releasable for initially a core must be readily and easily threaded over the elongated mandrel and after the web rewinding operation, the cores must be readily vstripped therefrom. Ordinarily, lock fingers are provided which are retractable and extensible through openings in the circumferential surface of the mandrels. In the past it has been customary to provide fingers that are normally in retracted position and that are extended through the openings in the mandrel wall by applying a compressive force to a core locking rod that is operatively connected to the locking fingers. Upon release of the compressive force applied to the rod, the fingers are retracted to release the core or core segments.

Several problems have beenv present in the prior art web rewinding machines, and one of these problems arises through the particular drive arrangement employed for rotating the mandrels during the web rewinding operation. Considerable web breakage has occurred during this operation because of the inability of the relatively Ithin paper webs to overcome the inertia of the rotating mandrels and reduce the rotational speed thereof as the web thickness increases on the cores. This problem will be better appreciated if it is realized that the papers handled by the machinery often have relatively low tensile strength, as toilet tissue, for example.

Another problem that has arisen is web breakage that is caused by vibration, and especially vibration of the mandrel. A large portion of the mandrel vibration has been caused by the stresses applied to the mandrel or partsthereof during the web winding operation. The vibration becomes particularly bad as the rotational speed of the mandrels approaches the critical speed; that is, the natural frequency of vibration of the mandrel, and stressing the mandrel at such time further aggravates the tendency toward vibration.

It is apparent that a need exists for a better mandrel structure, and it is accordingly an object of this invention to provide an improved mandrel structure that will overcome a number of the disadvantages present in prior art structures, and particularly those `set forth above. Another object of the invention is to provide a web winding mandrel and drive means therefor that permits the' lrelatively small tensionsthat can be applied by thin paper webs to overcome the inertia of the rotating mandrel structure to control and retard the rotational speed thereof. Still another object is in the provision of a clutch drive for rotating a mandrel in which friction pads engaging a drive wheel provide substantially the same fric;- tional or driving engagement therewith irrespective of the rotational velocity of the mandrel.

A further object is in the provision of a clutch mounted concentrically upon a mandrel and having a plurality of spring biased friction pads engaging a drive wheel, the friction pads being counterbalanced so that the frictional engagement Ybetween the friction pad and drive wheel remain substantially constant, irrespective of the rotational velocity of the mandrel. Still a fur-ther object is providing in a mandrel structure of the character described locking lingers for securing a core upon the mandrel, and in which the means for extending the locking fingers through the mandrel is normally under tension while the mandrel rotates for eliminating vibrational tendencies caused by stressing of the mandrel or its components. Additional objects and advantages will appear as the specification proceeds. An embodiment of the invention is illustrated in the accompanying drawing, in which- Figure 1 is a longitudinal sectional view of a mandrel A ing freely outwardly from the rotational support means` for the mandrel. However, in certain operative positions of the mandrel when it is incorporated in a web Vre- ;winding machine, the free end thereof is adapted to be supported, and in Figure l such a support means is illustrated.

In Figure l the mandrel is shown supported in spacedapart spiders 12 and 13 that together comprise a turret adapted to be rotatably driven by an appropriate drive mechanism, such as a Geneva drive 14. Since the turret, the Spiders 12 and 13 thereof, and the Geneva drive 14 form no part of this invention per se, the entire mechanism is not shown in the drawing and. will not be described in this specification. For details of a complete machine in which the mandrel structure A may be mounted, reference may be made to copending application Serial No. 299,108, now Patent No. 2,769,600, idenf tiiied hereinbefore.

The spiders 12 and 13 provide respectively bosses 15 and 16 that are contoured for receiving portions of the mandrel assembly therein, and which have threaded studs 17 extending outwardly therefrom that are adapted to project through caps (not shown) that will cooperate with the bosses for securely anchoring themandrel assembly Y in position within the spiders 12 and 13.

Rigidly clamped within the boss 16 is the enlarged end portion 18 of a sleeve 19 that is positionedjcoaxially about the mandrel 10, but is spaced therefrom so that the mandrel may rotate freely relative to the sleeve. Slidably mounted upon the mandrel is an elongated stop sleeve 20 having an end portion thereof received within the chamber 21 defined within the enlarged end portion of the sleeve 19, and having also a portion that extends laterally outwardly therefrom along the circumferential surface of the mandrel. The stop sleeve 20 is snugly received about the mandrel 10, and while being slidable with respect thereto, is slightly compressible so that the axial position of the stop sleeve upon the mandrel can be maintained by a clamp collar 22 that extends about the sleeve 20 and is effective to compress it tightly upon the mandrel. An antifriction bearing 23 is interposed between the enlarged end portion 18 of the sleeve 19 and the stop sleeve 20. The axial position of the bearing 23 upon the stop sleeve 20 is determined by a laterally extending flange 24 with which the stop sleeve 20 is equipped, and that provides on one side an abutment for the bearing 23. Adjacent the opposite side of the bearing the stop sleeve 20 is channeled for receiving a snap washer 25 that abuts the bearing 23. The bearing 23 then provides one rotational support for the mandrel 10. Y

Rigidly locked within the boss of the spider 12 is an enlarged tubular screw 26 having a threaded end portion 27 that extends outwardly from the boss 15 and along the mandrel 10. The screw member 26 is considerably larger than the mandrel 10, and while being coaxially positioned thereabout, provides considerable clearance between the mandrel and internal surface of the screw. The mandrel 1t) has coaxially positioned thereabout a drive sleeve 28 that is slidable longitudinally along the circumferential surface of the mandrel, but may be locked in position thereon by means of a clamp collar 29. Interposed between the tubular screw 26 and the drive sleeve 28 is an antifriction bearing 30 that provides the rotational support for the mandrel within the spider 12. The bearing 30 on one side thereof abuts an enlarged central portion of the sleeve 28, and on the other side thereof abuts a snap ring 31.

Threadedly received upon the end portion 27 of the screw 26 is an adjusting nut 32 that bears on one side thereof against the outer race of an antifriction bearing 33. The inner race of the bearing 33 bears against the i drive ring 34 of a friction clutch assembly designated generally with thenumeral 35. The drive ring 34 is splined or keyed about the drive sleeve 28, asV shown in Figure l, so that the drive ring and drive sleeve cannot rotate relative to each other. The antifriction bearing 33 serves as ya thrust bearing working between the mandrel 10 and -the spider l2 through the intermediate parts described. j

The clutch assembly, as is shown most clearly in Figure 2, comprises, in addition to the clutch ring 34, a plurality of equally spaced-apart leaf springs 37 that at their innerY ends are received within appropriate slots provided in the ring 34 and are secured therein by means of the pins 3S. The outer end portions of the springs -37 are slightly arcuate and bear toward the right, as viewed in Figure l, so as to urge the friction members or friction pads 39 into engagement with the face 40 of a drive wheel or pulley 41 having a circumferential V- shaped channel 42 extending thereabout adapted to rcceive a V-shaped drive belt therein. The pulley wheel 41 is mounted upon the sleeve 19 by means of spacedapart antifriction bearings 43 and 44 that permit the drive pulley to rotate freely relative to the sleeve 19.

The friction pads 39 may be formed'of any suitable friction material and, for example, liber or cork may be employed. The friction pads are secured to the leaf springs 37 by means of screws 45 'thatV extend through the pads, through the leaf springs and threadedly receive thereon a pair of lock nuts 46 and 47 that serve as counterweights or balances for the friction pads and serve a function that will be described hereinafter. It is apparent from an inspection of Figure l that as the pulley wheel 41 is rotated, it frictionally engages the pads 39 and through the clutch ring 34 and drive sleeve 28 is effective to rotate the mandrel 10.

Mounted within the hollow mandrel 10 in spacedapart relation are a pair of bronze bearing members 48 and 49 that may be secured in axial positions within the mandrel by means of pins or set screws, such as the set screw 50. Slidably mounted within the bearings 48 and 49 is a core locking rod 51 that is elongated and extends substantially the entire length of the mandrel 10. Pinned to the rod 51 intermediate the bearings 48 and 49 is a stop 52 that serves as a seat for a coil spring 53 that at its opposite ends seats upon the bearing 49. Adjacent the stop or seat member 52 is an enlarged liange 54 that may be formed integrally with the rod 51 and that serves as a stop that abuts the inner side of the bearing 48 and limits axial movement of the rod toward the left, as viewed in Figure l, under the biasing action of the coil spring 53. Pivotally secured within appropriate slots provided in the rod 51 are a plurality of locking fingers or dogs 55 that extend into circumferential openings provided in the surface of the mandrel 10. While in Figure l only one locking linger 55 is illustrated, it will be apparent that a plurality of locking lingers are required and the locking lingers Will be arranged axially along the mandrel and rod 51in spaced-apart relation, and at least one locking finger will be provided for every core segment carried by the mandrel 10. Axial movement of the rod 51 is guided by a glide member or collar 56 that is locked on the rod 51 by means of a set screw 57. The guide S6 is freely slidable longitudinally within the mandrel 10.

A bearing 58 is positioned within the outer free end of the mandrel 10 and the threaded end portion 59 of the rod 51 extends therethrough and threadedly receives thereon an inner guide sleeve 60 and an outer locking moving V-shaped belt.

guide sleevev 61. The outer end of thefguide sleeve 61 is tapered, as shown in Figure 1, vand is adapted to extend through a self-aligning antifriction bearing 62 provided within an opening 63 through the head 64 of a `guide support arm 65. A bifurcated guide 66 is secured to the arm 65 by a cap screw 67, and the spaced legs thereof are positioned adjacent the opening 63 and serve to guide the sleeve 61 into the self-aligning bearing 62 of the arm head 64. YThe support arm 65 is provided by a web rewinding machine, such as the one described briefly hereinbefore, and is movable between the position shown in Figure 1 wherein it is supporting the free end portion of the mandrel and a retracted position wherein it is withdrawn from the mandrel 10 and moved clear thereof. The support 65 functions to stabilize the mandrel 10 during rotational movement thereof in certain of the operating stations of the web rewinding machine.

It is clear from Figure 1 that the coil spirng 53 tends to bias the rod 51 toward the left wherein the locking fingers 55 are extended outwardly through the surface of the mandrel 10 when a core is threaded onto the mandrel 10 and when the lwound core orA core segments are stripped therefrom the locking fingers must be Vretracted into the mandrel, as is shown in Figure 1, so as to afford free movement of the core upon the mandrel. The core is free ofthe mandrel only during the period when a core is inserted onto the mandrel and where the wound core is withdrawn therefrom.V -In order to move the rod 51 to the right and withdraw or retract the locking fingersy 55, a stationary cam 68 may be provided by the web rewinding machine at the loading and feeding stations, and as the turret or spiders 12 and 13 carry the mandrel 10 through various operating stations, the cam 68 will be engaged by the laterally-projecting end portion of the rod 51 and will function to move the rod inwardly to retract the locking fingers.

Operation In operation of the apparatus, the mandrel assembly A will first be located with the cam 68 engaging the rod 51 to retract the locking lingers 55. At the same time the support arm 65 will be withdrawn from the guide sleeve 61. The mandrel 10 will then be in condition to have an elongated continuous paper core inserted thereon. The core will be moved onto the mandrel until it abuts the stop sleeve 20. inbefore, the stop sleeve 20 is slidable upon the mandrel 10 when the clamp collar 22 is released so that the precise position of the stop sleeve may be adjusted for accurately positioning a core upon the mandrel. After a core has been lthreaded onto the mandrel, the mandrel assemblywill be carried to subsequent operating stations inA a web rewinding machine wherein the core will be cut into segments, glue applied thereto, and finally the mandrel assembly will then be moved toward a web winding station.

In the movement of the mandrel assembly into the web winding station, the V-shaped channel 42 engages a The wheel 41 will then commence to rotate and through the face 40 thereof which bears against the friction pads 39, the leaf springs 37, the ring 34 and drive sleeve 28 to which it is secured, the mandrel 10 will be rotated. At such time the rod 51 will be free of the cam 68 so that the core or core segments will be locked against rotational movement rela- Y tive to the mandrel 10 and the support arm 65 will be in the position shown in Figure 1.

After a web has been wound upon the core, the mandrel assembly will be moved into a stripping station and at this time the cam 68 will move the rod 51 into the position shown in Figure l, and the arm 65 will be retracted from the mandrel so that the wound core segments can be stripped therefrom.

The guide 66 on the arm 65 initially engages the pointed guide sleeve 61 as the arm moves into position As has been brought out here- Vis a self-aligning bearing, the guide sleeve 61 and con.'-

sequently the rod 51 and mandrel 10 are rotatably supported within the arm 65 with no stress or strain imparted to the mandrel assembly by the support. The mandrel assembly, in other Words, is supported at its free end in the normal position. This feature is important in reducing vibration of the mandrel for it has been found that anyvstresses imparted to the mandrel, directlylor indirectly, amplify any vibrational tendency of the mandrel.l

Vibration is further minimized by placing the rod 51 under a slight tension when it is in its normal position with the locking fingers 55 projecting outwardly from the circumferential surface of the mandrel and lockingly engaging a corereceived upon the mandrel. The tension is caused by the coil spring 53 which biases the rod toward the left, as viewed inlFigure 1, and the locking fingers 55 which are engaging a core and thereby tend to prevent or to limit the extent of movement of the arm 51 toward the left. kNormal tension Within the core locking rod 51 is contrasted with the usual compression of suchfa locking rod during the time lthe locking fingers are in extended position.

Through most of the operating stations in an automatic web rewinding machine, the drive wheel 41 is out of engagement with the drive belt employed in the machine, and if the mandrel is to be rotated, rotational movement is imparted thereto through some other arrangement. However, when the mandrel is moving into the web winding station, the V-shaped groove 42 progressively approaches and finally engages a complementary V-sh-aped drive belt and rotation of the mandrel commences. Ony the other hand, as the mandrel assembly is being moved out of a web-winding station, the drive Wheel 41 progressively moves out of engagement with the drive pulley `and rotation of the mandrel is shortly termin-ated. As has been brought out before, the velocity or rotational speed of the mandrel 10 must be progressively decreased as the extent or amount of webbing wound upon the cores increases. It is desired to effectuate an automatic decrease in the rotational velocity of the mandrel corresponding precisely to the amount of webbing wound about the mandrel -at any time. This automatic regulation` is provided by the tension exerted by the web which results in a resistance to free movement in the mandrel. The tension that can be exerted by thin paper, such as tissue paper, is very slight, but with the clutch arrangement described, that tension, however slight, can be made to retard and progressively slow down the rotational velocity of the mandrel. There are several reasons for this.

In the first place, a plurality of friction pads 39 are provided, and, as a result, there is a limited frictional engagement with the face 40 of the drive wheel. 'Further, each friction pad is individually biased by a leaf spring into engagement with the face of the drive wheel and an equal distribution of the frictional engagement with the face 40 is provided thereabout.

Another reason is that the frictional engagement between the pads 39 and face 40 of the drive wheel can be accurately controlled and regulated. If it is desired to decrease the frictional engagement, the nut 32 is turned so as to advance it toward the spider 12, thereby decreasing the force imparted by the thrust bearing 33 against the clutch ring 34. Rotation of the nut 32 in the opposite direction will serve to increase the frictional engagement of the pads 39 with the face 40. The nut 32 is readily accessible and permits quick and easy regulation or adjustment of the driving friction between the pads 39 and drive wheel 41.

Another important reason is that the frictional engagement of the pads 39 with the face 40 is substantially independent of the rotational velocity of the mandrel 1t).A

Thus, when the mandrel is rotating at a relatively high.

speed, the driving friction is substantially the same as:

when the mandrel is rotated at very, slowspeeds. The

reason for this is that the lock nuts46 and'47 'are actualdetail View of a single pad 39, counterweight assemblyV therefor and leaf spring 37, it will be seen that the friction pad 39 is spaced forwardly of the line wherein the leaf spring 37 is received within and supported by the ring 34. The distance between the center of the pad 39 and leaf spring 37 is designated in Figure 3'with the letter Y. The nuts 46 and 47, which comprise the counterweight, are spaced rearwardly of the leaf spring 37 land the distance between the center of gravity of the counterweight and the'leaf spring at its point Vofengagtiment with the ring 34 is designated with the letter X.

As the ring 34 rotates, the centrifugalv force within the pad 39 will tend to rotate the spring 37 in a counterclockwise direction about its point of engagement with the ring 34. Since the centrifugal force increases with the velocity of rotation of the ring 34 V(also the mandrel 10 to which it is secured), the pad 39 would tend to be withdrawn from the face 40 of the drive wheel 4l and the frictional engagement therewith would decrease. On the other hand, as the speed of the mandrel or ring 34 decreased, the Vpad 39 would tend to more rmly engage the face 40 of the drive wheel. There would then be a changing frictional drive force that would vary with the rotational velocity of the mandrel.

With the counterweight arrangement. shown, however, the center of gravity of the counterweight or nuts 46 and 47 is spaced rearwardly by a distance X from the leaf spring 37 and the distance X is substantially equal to the distance Y. Thus, the centrifugal force of the counterweight assembly wound tend to rotate the leaf spring 37 in a clockwise direction about the friction ring 34 and substantially cancels the centrifugal effects on the leaf spring 37 of the pad 39. Thus, irrespective of the rotational velocity of the mandrel 10, the frictional engagement of the pads 39 with the face 40 of the drive wheel is substantially constant, and since that force can be adjusted, as has been described, small tensions that can be exerted by thin paper webs are sucient to-control and automatically regulate the rotational velocity of the mandrel as required in accommodating the rotational velocity to the amount of webbing wound about the mandrel.

While the nuts 46 and 47 act as counterbalance for friction pads 39, it may not be always desirable to eiect a completely balanced condition. With the arrangement shown, it is possible to have a very light but suicient pressure between the friction pads and the mating surface when the mandrel is at its highest speed at the transfer point when the web starts winding on the core.

As the roll builds up and the mandrel slows down, it is also possible to. have this pressure progressively increase so as to achieve constant tension, if desired. More often a curve between constant torque and constant tension will produce a better wound roll and by proper counterbalancing of the friction pads, it may be achieved.

While the specific embodiment of the invention illustrated in the drawing has been described in considerable detail for purposes of fully and completely disclosing the invention in a useful setting, it will be Vapparent that those skilled in the art may vary these details substantially without departing from the spirit and principles of the invention.

I claim:

1. In a mandrel structure adapted for use in web rewinding operations, an elongated hollow mandrel provided witha plurality of openings in the circumferential wall thereof, means supporting and rotatably driving said mandrel adjacent an end thereof, a self-aligning bearing Yfor said mandrel adjacent the opposite end thereof, said mandrel being adapted to receive a core thereon, spacedapart support members mounted within said mandrel and having aligned bores therethrough lying on the longitudinal axis of the mandrel, a core locking rod slidably and axially mounted within said bores and being equipped with a plurality of core-locking fingers aligned with said openings and being movable inwardly and outwardly therethrough upon axial movement of said rod relative to said mandrel, one end of said rod extending out of the opposite end of said mandrel and supported by said self-aligning bearing, said rod remote from said one end being equipped with flange means, said flange means being positioned between said lsupport members, spring means about said rod extending between said ange means and the support member adjacent said one end, said spring means normally biasing said rod in a direction to extend said locking fingers through said openings and cooperating with said fingers for maintaining the rod under tension at such time, and means for moving said rod in a direction opposite to the urging of said spring means to retract said fingers through said openings.

2. The structure of claim 1, in which said self-aligning bearing is equipped with a guide member engageable with said rods one end for guiding said rod into said bearing.

References Cited in the file of this patent UNITED STATES PATENTS Kwitek et al Nov. 6, 1956 

